Approximately 20% of adolescents who are obese also smoke, which accounts for approximately 5 percent of the population. Independently, both obesity and cigarette smoking put people at great risk for a number of health conditions. However, the combination of being both obese and a smoker increase risk drastically. Individuals with a BMI greater than or equal to 35 and who also smoke have a mortality risk 6 - 11 times that of healthy weight never-smokers. Furthermore, smoking status is a consistent barrier to successful weight loss in both adults and adolescents, with obese smokers more likely to drop out of treatment and least likely to make significant weight losses. Unfortunately, obese smokers are an underrepresented group in the treatment and prevention literature, and little research to date has identified behavioral factors that increase the risk of becoming an obese smoker. In response to the need for research that identifies behavioral attributes of this at-risk group, the primary objective of the proposed research will be to compare a sample of adolescent obese smokers to obese non- smokers, healthy-weight smokers, and healthy-weight non-smokers using both self-report and laboratory- behavioral assessments of impulsivity. The inclusion of behavioral impulsivity assessments stands to yield highly specific information about the behavioral styles of adolescent obese smokers. Such information may lead to treatment-program modifications to improve outcomes for those obese adolescents most challenged in their efforts to make significant lifestyle behavior changes. A secondary objective of the proposed research will be to explore the relationship between impulsivity and particular patterns of eating behavior. Recent evidence indicates that more impulsive individuals engage in more impulsive eating. However, these studies almost exclusively used self-report measures of impulsivity and none had examined the eating behavior of obese smokers and non-smokers. Results from this additional aim may improve interpretation of our primary question, by allowing the exploration of specific eating motivations and behaviors both across and within the different weight- and smoking-status categories.